noun
sociable person; social butterfly
Describes someone who actively enjoys socializing and has a wide circle of acquaintances.
彼女は交際家で、週末はいつも誰かと会っている。
She is a sociable person and is always meeting someone on weekends.
Compound of 交際 (kōsai, 'socializing') + 家 (ka, 'person'). The exact historical derivation is uncertain, but the word follows a common pattern for describing a person with a particular trait.